Magnetic media represent a common form of digital data storage for computer systems. Among the magnetic storage systems, linear tape drive systems are in use in many enterprise applications for data management. Magnetic media are also currently used in hard disk drive systems. Hard drive systems typically have a larger storage capability than linear tape drive systems owing to their higher areal density, linear density, and track density. Areal density is a physical measure of storage systems that relates the number of data bits per unit surface area of magnetic storage media. Similarly, linear density is a measure of the number of data bits per unit length of data tracks, and track density is the number of data tracks that can be packed into a given form of magnetic media. In general, a larger density value corresponds to a higher storage capacity for a magnetic storage system.
In one conventional tape design, the roller guide assembly employs a smooth surface with which the magnetic tape is in contact during a read write operation. The smooth roller surface does not allow for a sufficient frictional contact force to be developed thereon. The insufficient frictional contact force causes the magnetic tape to develop a significant lateral motion during a read write operation.
Yet another problem with the conventional design of linear tape drive systems is the large spacing between the rollers, which causes the magnetic tape to be unsupported over a large span. The unconstrained magnetic tape between the rollers tends to develop lateral motion that generates a high frequency lateral disturbance, as the magnetic tape leaves the rollers and the supply reels, that can propagate to the recording head.
The performance of conventional linear tape drive systems is further inhibited by placing the actuator containing the recording head distally from the rollers. As a result, any lateral disturbance in the magnetic tape will propagate to the recording head. Typically, the actuator that houses the recording head is designed to perform track following by closed-loop servo control. The track following servo control commands the actuator to move in the lateral direction so as to follow a target data track on the magnetic tape.
As the magnetic tape experiences high frequency lateral disturbances, the track following servo control may not be able to maintain the desired track following performance within its frequency bandwidth. The resulting error due to the inability of the actuator to follow a target data track, herein also referred to as a track following error, thus imposes a performance limitation on the track width of the magnetic tape (in a conventional design) in that it cannot be smaller than the track following error. This limitation thus dictates the track density of the conventional design of linear tape drive systems.
In view of the unresolved problems with the conventional designs of the linear tape drive, there is a need for an improved design that can effectively address the forgoing problems. Preferably, the improved design should be able to reduce substantially high frequency lateral disturbances of the magnetic tape. Moreover, the improved design should also be able to significantly reduce the track following error. By successfully resolving the forgoing concerns, an improved design should enable linear tape drive systems to achieve a higher track density, and hence a larger storage capacity.